How to Fix Slow Coffee Drainage: Easy Pour-Over Tips for Better Flavor

 Compared with controllable variables like water temperature, grind size, dose, and ratio, brew time tends to be more random and passive. For many beginners, it’s also one of the hardest parameters to master—yet it’s the best indicator of whether your flow rate is on track.

Many home brewers have told me that they often run into slow drainage during a pour-over, which forces the brew time to drag on. To prevent over-extraction, some people even lift the dripper off early as a last-minute rescue. So what causes this? And more importantly—how do you fix it?

Brew Time

Whether online or face-to-face, I always emphasize that your final pour should ideally finish between 1:30 and 1:40, and the total drawdown should wrap up around 2:00 ± 10 seconds.

In other words:

• Shorter than this → flow rate is too fast → likely under-extracted

• Longer than this → flow rate is too slow → likely over-extracted

This isn’t the only correct standard—but it fits my usual brew framework:
15g coffee, 1:15 ratio, grind size yielding 70–80% pass-through on a 20-mesh sieve, and a 3-stage pour.
Within roughly two minutes, the coffee grounds should have enough even contact with the water, keeping extraction stable and predictable.

If your brew passes 2:10 and the water still hasn’t drained, and you notice very thin crema with a few scattered white bubbles—or even dry grounds exposed on the edges—this means the water is being blocked by the coffee bed. By the time it makes its way down, it has likely dissolved too many late-stage compounds—mainly bitter, harsh, and astringent flavors. In short: the coffee won’t taste good.

To fix it, we first need to figure out why the water is pooling.

1. Too Much Fines

Most slow-drain issues are related to grind size. If the grind is too fine, water struggles to pass through. Finer grinding also produces more micro-fines, which increase resistance and slow the flow.

For reference, the grind size I use in my shop for pour-overs is about table-sugar coarse, around 70–82% pass-through on a 20-mesh sieve.
Machine references:

• EK43S: 9.5–11

• Comandante C40: 22–26 clicks

  

But here’s the key:
Every grinder, expensive or cheap, produces fines—this is unavoidable.

High-quality grinders cut beans cleanly, producing consistent particles with fewer fines. Low-quality grinders often crush before cutting, creating a wide range of particle sizes and a high amount of fines—basically “too many fines and overly large boulders.”

If your brew stalls past 2:20, the coffee bed looks muddy while large particles are still visible, and the flavor is weak but overwhelmingly bitter, then your grinder is likely the main culprit.

2. Pouring Technique

A lot of people love circular pouring just like I do. But some keep swirling big circles from bloom all the way through, aiming to wash away all the foam. This raises the water level, but toward the end it can thin the coffee bed walls and push more particles downward—creating a dense layer of fines at the bottom that blocks drainage.

Another common issue is weak agitation during the bloom, which fails to lift and loosen the grounds. If fines cluster and settle at the bottom early on, the brew eventually becomes a slow gravity drip along the filter walls.

3. Light-Roast Coffee

You may have noticed that slow drainage often happens with bright, fruity coffees—such as Ethiopia, Panama Geisha, and other high-altitude beans.

Why?

• Light roasts + high elevation = dense structure

• Dense beans absorb water more slowly

• They also generate more fines during grinding

When you pour in circular motions, water movement pushes fines around—and these tiny particles often reach the filter paper first, forming a clogged layer.

How to Fix Slow Drainage

1. Adjust the Grind

Start by grinding 1–2 steps coarser.

• If flow improves but the flavor becomes weak → try raising water temperature by 1–2°C or slightly lowering the ratio.

• If it still clogs → consider using a sifter to remove some fines or upgrading to a better grinder.

2. Change Filter or Dripper

If you don’t plan to change equipment or sift, try switching to a dripper or filter that has better flow-through properties. Sometimes that alone helps dramatically.

3. Use the “Mound Pouring” Technique

For those who frequently experience slow drawdown, here’s what I recommend:

• After blooming, pour in small circles from the center, letting the coffee grounds naturally mound up and push outward.

• This forms a tall “coffee wall” (about two-thirds the height of the dripper).

• This shape keeps the center thinner, letting water drain smoothly.

• Finish the final stage with gentle, small-circle pours, ensuring even saturation while preventing grounds from being washed down the dripper walls.